The present disclosure relates to semiconductor structures, and particularly to semiconductor fin structures including multiple heights and/or multiple compositions and a method of manufacturing the same.
A finFET is a field effect transistor including a channel located in a semiconductor fin having a height that is greater than a width. FinFETs employ vertical surfaces of semiconductor fins to effectively increase a device area without increasing the physical layout area of the device. Fin-based devices are compatible with fully depleted mode operation if the lateral width of the fin is thin enough. For these reasons, fin-based devices can be employed in advanced semiconductor chips to provide high performance devices.
In conventional semiconductor fin devices, the height of semiconductor fins is fixed, and the output of the semiconductor fin devices is controlled by the number of semiconductor fins within each semiconductor fin device. For example, the on-current of a fin field effect transistor is digitally changed by changing the total number of semiconductor fins within the fin field effect transistor, while the semiconductor fins have the same height. As a result, the output of conventional semiconductor fin devices on a same substrate is quantized, and incremental adjustment of the output by an amount less than the output from a single semiconductor fin is difficult to achieve.